Apparatus for manufacturing lamellar tubing



April 8, 1952 P. R. GOLDMAN E-rm.v 2,591,928

y APPARATUS FOR MANUFACTURING LAMELLAR TUBING original FiledMay 28, 1943LIN l I :ve miams: ,Pau/ZR. 603

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Patented Apr. 8, 1952 APPARA'IUSA FOR MANUFACTURING LAMELLAR TUBING PaulR. Goldman and Rudolph Alt, Andover,

Mass., assignors to Plymold Corporation, Lawrence, Mass., a corporationof Massachusetts Original application May 28, 1943, Serial No.

1946, Serial No. 666,206

2 Claims. (Cl. D14-268) This invention relates to lamellar tubing andthe manufacture thereof, and aims to provide apparatus adapted for therapid production of indeterminate continuous lengths of such tubing fromwood veneer, plywood and other flexible sheet materials, and to improvetubing of that class.

This application is a division of our copending application Ser. No.488,854, filed May 28, 1943, and now issued as Patent No. 2,402,038,dated June 11, 1946.

In the accompanying drawing illustrating somewhat diagrammatically oneexemplary embodiment of the invention,

Figs. 1, 1a and 1b, the two latter a continuation of Fig. 1 are aschematic showing in plan of a series of stations of a typical apparatusfor forming the endless tubular product.

The apparatus as a whole makes provision for a succession of stages orphases each involving one or more operative steps, all performed along aseries of independently controllable but synchronized and coordinatedstations. The mechanical and electrical equipment at the variousstations is disposed as an organized assembly of units distributed alonga sectionalized or other suitable frame represented in the drawings asincluding longitudinal members 2 and cross supports 3, the constructiondesirably being such that units may be added or omitted as particulartubing products and uses may require. In the illustrated example somesixteen such stations or operational phases are indicated generally bythe reference letters A to P, the supporting frame as a whole desirablybeing of a sectional character. To promote proper relative timing of allmovements and phases of the apparatus as a whole the several units orsections are represented as operated from a common drive shaft 4rotatably supported along the machine frame in suitable bearing brackets4'..

The base or inner veneer layers which provide a core for the tubingproduct are developed upon an elongated cylindrical or other former ormandrel 5. This is of a length to extend at least through the initialspiral wrapping and bonding stations B and C and preferably along one ormore succeeding stations, herein through station H. While in someinstances a rotary mandrel may be employed, we prefer a stationary non-.rotating mandrel such as here shown at 5. It

accordingly may be fixedly supported at its initial or rear end instation A. Forwardly thereof it is freely supported for reception ofwindings of veneer, as by means of radially yieldable roller Divided andthis application May 1,

2 or other bearings at or between stations, as at the cross supports 3and which in effect afford the mandrel a floating mount.

The tubular product comprising the several superposed and interbondedveneer layers or wraps is caused to progress along the non-rotatedmandrel to the forward terminus thereof and thence on throughout thefull length of the machine in a continuous length of indeterminateextent. As noted, the one or more inner or core wraps of the veneerpreferably are spirally formed. In feeding or advancing them along andpast the mandrel, any tractive or progressing ac- 'tion should be soapplied as to avoid the tendency of opening or separating the spiralturns. Accordingly our process desirably includes a continuoussupporting of the tubing by means adapted to travel with it and todistribute the progressing force along the entire length of thedeveloping spiral tubing, in effect overlapping and bridging acrossbetween its multiplicity of spiral turns. This may be accomplishedthrough the medium of a progresser element, feeder or barrierrepresented as a longitudinally continuous web or layer 6 of foldablesheet material.

This carrier is conducted from a suitable sup-'- ply, along onto andabout the mandrel, concentrically between it and the spiral laid veneerabove-mentioned. Selected flexible sheet matevrial of adequate tensilestrength may be employed for the purpose, such for example as a fairlyheavy waxed paper strip, a light-weight cotton 4or other fabric, web orthe likeV including thin wood veneer and other flexible materials. Asupply roll 6a of such material is rotatably mounted at or adjacentstation A, as upon a bearing shaft 1, in position to be drawn upon. Thecarrier strip 6 from the supply passes about a guide roll 8 andforwardly through a former 9 shaped and positioned to fold thelongitudinal 'side edges of the advancing carrier strip laterally aboutthe mandrel 5, so as to enclose or partly enclose it. At the start ofa'manufacturing operation, such feeder or carrier strip 6 has itsleading end threaded through the former 9 and forwardly along themandrel 5 to or beyond the point, herein at station B, where the firstveneer spiral wrapping is to be applied, such wrapping then serving tohold the strip in position about the mandrel.

At station B, a first strip I 0 of thin wood veneer is spirally applied,with the succeeding veneer turns in closed or substantially closededgewise abutting relation. Such veneer strip may be of the character asdescribed for example in Goldman application Ser. No. 462,800, copendentwith our parent application and now issued as Patent No. 2,388,479,dated November 6, 1945, extensive lengths of this strip material beingprepared and supplied in roll form.

A supply roll II of such veneer strip or tape is rotatably mounted on anarm I2 pivoted as at I3 on a revoluble wrapper head indicated generallyat I4. |The latter is driven by suitable connections I5, desirably of apositive character, from the main drive shaft 4, through an interposedvariable speed control device I6, aifording independent adjustment andcontrol of .the speed of the wrapping operation at this station B. Itwill be seen that the bodily revolution of the veneer tape supply rollor drum II about the mandrel is effective to wind spirally onto thepaper, veneer, fabric or like carrier strip 6 on the mandrel a layer ofthe veneer stripping havingA a direction of wind, indicated as righthandat station B correspondingV to the direction of revolution of thewrapper head, assumed in .this instance as clockwise as viewed from therear end of the machine, at the left in Fig. 1. This initial veneer Wrap'I0' as at station B may be of either hand, subsequent wraps preferablybeing alternately opposite to the one preceding.

From station B 'the initial veneer layer I0 is advanced along themandrel 5 together with the carrier web 6 whereby undesired separationof the Vspiral turns is avoided, to station C. There a second layer ofveneer stripping is spirally applied. Similar veneer wrapping mechanismis provided at station C, like parts accordingly being indicated bysimilar reference numerals as for station B. These include a furtherveneer supply roll II rotatable on a pivoted arm I2 and bodily revolublewith the wrapper head I4 actuated from the common drive shaft 4 throughconnections I5 again including a variable speed control I6. The gearingis here arranged to afford direction of revolution for the wrapper headopposite that at thel preceding station B.

Attendant on the formation of the' second spiral Vveneer wrap 20, thetwo initial Vlayers I0 and 20 are united throughout their entire lengthsby the medium of a plasticizable bonding agent, under the application ofheat and pressure. For this purpose we employ a plasticizablethermosetting or thermo-plastic bonding agent of the synthetic or other.resin type adapted for setting or polymerizing in the presence ofvpressure and heat. While we prefer for the purpose of phenolic cement,glue or like adhesive and impregnating agent, various materials areavailable, including those of the urea type and others as more fullydisclosed for example in our parent application and others identifiedtherein.

The selected bonding agent preferably is applied as a step in thepreparation of the veneer strip or tape supply rolls, as a coating cr ajuxtaposed .layer which is dried before the strip is wound into the formof a supply roll. But one layer or coat of the bonding agent generallyis required between any two succeeding veneer wraps. Hence it may becarried either at the outer face of a rst roll supply, such as that forstation B, or at the' inner face of` any following roll supply, such asfor station C and-others subsequent. Or as to any stations except thefirst and last, the bonding material may be supplied at both faces ofthe veneer strip. The process as a whole is facilitated by thuspreliminarily applying the bonding agent to the' veneer strip of thesupply rolls, but in some instances the agent may be applied to orinserted between the succeeding veneer layers in the course of theadvance of the tubing product through the machine.

The tubular veneer layers I0 and 20, as well as the others, are causedto advance, progress or travel bodily along the forming mandrel 5 bymeans to be referred to later in connection with station D and others;in the course of this travel the veneer layers are subjected to heat andpressure so calculated and timed with respect to theparticular bondingagent employed as to set or polymerize the same at least adequately toafford the progressing tubular structure a selfsustaining integralcharacter. That is, the veneer layers to be joined such as I0 and 20 ofstations B and C receive a heat and pressure treatment such that upontheir arrival at a next station they are sufficiently rmly set toreceivea further superposed veneer layer without likelihood of beingdeformed, separated or otherwise disturbed by the latter. Thispolymerizing,-setting and drying of the bonding agent need` not bewholly complete or final between successiveY wrapping stations andgenerally may be continued and supplemented in the course of similartreatment of succeeding layers, so that at the delivery station P acompleted tubing product is endlesslyy deliveredI subject to such, ifany, bufhng, coating or other finishing treatment as may be desired in agiven case.

While the heating and pressure treatment may be variously accomplished,we have found particularly adapted to the purposes of our process atreatment involving the application of electric energy either of thehigh-frequency or radiofrequency character or as utilized in electricalresistance heating. `Accordingly we have herein diagrammaticallyindicated in association with station-C, and various subsequentstations, means whereby the bonding agent is subjected to heat createdby high-frequency or radio-frequency current `while simultaneously thelayers to be bonded are placed under pressure tending to compact andunify them. Heating of the character referred to, sometimes termeddiathermic, may be in genera-l such as described for example in BritishPatent No. 310,925, U. S. Patents Nos. 1,813,425 y and 1,900,573 andothers such as 2,087,480 and 2,173,622.

Such heatingand pressure means as here diagrammatically shown includesone or more rolls 22 `mounted forf- -rotatable pressing engagement uponand -around the outer surface of the then outer or second veneer wrap20, in opposition to the mandrel 5 utilized as aformer or die. Thesepressure rollsr 22 -or their surface portions are of metal or otherconductive material suitably insulated from' theirl supporting means.They are simultaneously utilized as electrodes, being connected incircuit with one side, either positive or negative, of. a source `ofhigh-frequency or radiofrequency current, as indicated diagrammaticallyat station C. .The other electrode is as herein shown'presented' by themandrel 5 itse1f, the latter.being*insulated'from its bearing supportsand beingV connected with the other side of the current supply, as forvexample the positive side as indicated at station A.

Passage of the high-frequency current between the. pressurek rollers andthe mandrel as at station C acts to heat and polymerize the bondingagent between the two concentric veneer Wraps wand 2D, creating the heatlargely in or closely adjacent the bonding matter itself', with apenetratve action and in such manner that any injurious effect on theveneer is avoided. The roller pressure-electrode elements 22 are ofsufficient extent axially of the forming tubing to apply the desiredheat and pressure over a substantial length of the tubing, adequate toaccomplish the setting and drying of the bonding agent during the timedprogress of the tubing beyond station C. Said elements may comprise asingle elongated set or a series of successive sets distributed alongthe tubing.

It will be evident that the polymerizing time for the particular bondingagent employed is a main factor in determining the rate of advancingtravel for the forming tubular structure. The several operationalstations are so arranged and correlated, and the rate .of travel of thetubing product 1s so timed that in the course of progress from onewrapping or layer-applying station or point to the one next succeedingthe bonding agent is `at least partially polymerized, to the unifyingextent as previously described, adequately to render the productsubstantially self-supporting or form-retaining, as to each succeedingveneer layer and as to the accumulating unified plurality thereof as awhole.

At station D We have represented schematically a progressing oradvancing means as particularly appropriate in association with theassumed stationary and non-rotating mandrel 5. It comprises as a mainelement an endless flexible band or feeder belt 25. One or more fullturns of this belt are applied directly around and in grippingengagement with the outer surface of the tubing lll-20. The belt alsopasses over one or more carrier pulleys on a revoluble head or plate 26having a supporting sleeve bearing 21 surrounding and concentric withthe tubing but spaced from it. This head 26 is driven through suitableconnections 28 from the main drive shaft 4, again through a variablespeed control unit 29.

The feeder belt 25 as stated has onelor more full turns, inside-by-sicle relation, around the tubing, where it accordingly presentsa spiral or screw-like gripping formation. Revolution of the belt as awhole, while the belt itself is kept taut between its carrier pulley andengaged tubing, produces a similar effect upon the latter as if thetube-gripping portion were in fact a screw being turned on the tubingbut held against travelling along it. Since similarly the belt, beingpositioned in the axial direction by its supporting head 26, cannotprogress along the tubing, the latter itself is forced to progress at arate determined by the speed of revolution of the belt and head 26. Thisrate of feeding or progressing movement thus supplied to the tubing maybe accurately controlled and regulated through the medium of the speedcontrol 29. In this connection the function of the paper or otherflexible carrier web 6 will be appreciated. Since this tubular orvpartlytubular carrier layer is subject to the gripping action of theprogressing means a major portion of the advancing force is received byit rather than by the veneer layers while they are being dried and set.The carrier web, which may be continued throughout the entire length ofthe tubing, serves as a longitudinal tie or bridging connection betweenthe Various spiral turns of the tubing, relieving them of any tendencyto be separated. Since in actual practice the required feeding effortaxially is relatively slight, a carrier web of ordinarily fairly heavywaxed paper generally is found adequate for the purpose.

Beyond the progressing or feeding station D any desired number ofadditional spiral applications of veneer stripping are made. We haveherein represented by way of example a further series of three stationsE, F and G, each of which may be substantially similar as alreadydescribed in connection -with stations B and C, including heat andpressure means as exempliiied at the latter station. The direction ofwind is alternated, the several wrapping heads and their driveconnections, the latter again including speed control devices l, beingsuch as to afford the desired reversal of lay and overlapping of edgejuncture in successive layers. In the illustrated example a right lay 35is indicated at station E. over the preceding left lay 20 at station C,and followed by left and right wraps 45 and 50 respectively at stationsF and G. Heat and pressure treatment adequate for at least partialpolymerizing of the bonding agent desirably is applied at each of thesestations, similarly for example as explained in connection with stationC. Thus it is evident that the operation at or in association with eachstage or station is sufficiently complete to render the strip thereserved and applied to the work substantially self-sustaining orform-retaining, that is, each veneer wrap or layer is subject to a heatand pressure setting or polymerizing treatment prior to the serving andlaying of the superposed layer next succeeding. In this manner a tubingproduct of maximum strength and rigidity, particularly in the radialdirection as desired for the inner or core element of the tubing, isproduced.

At station I-I We have indicated another progressing or advancing means25 to 29. This may be such as previously described in connection withstation D. Depending on the lparticular characteristics, as to weight,wall thickness, and strength desired for the given tubing product, anyplurality of the alternately opposite spiral veneer windings may beemployed. The apparatus as here shown by way of illustration makesprovision for ve inner or core spiral-formed layers, which plurality isupon the average found to be sufficient in the greater number ofinstances, for tubing up to diameters of 3 to 5 inches 01' more. Ifadditional innerJ wraps are desired other wrapping stations may beinserted. Conversely, if a less number of core veneer layers arerequired, any one or more of the stations C, E, F or G may be renderedinoperative, the corresponding wrapping head I5 being temporarilydisconnected as by a zero setting of the speed control or throughsuitable clutch mechanism.

The forming mandrel 5 is extended through the successive wrappingAstations from station A to a stage such as to insure adequate supportfor the forming core. In the diagrammatic showing of Figs. 1, 1a, thismandrel 5 is continued through Aand terminates shortly beyond stationI-I, as indicated by the dotted line and the numeral 5 on Fig. la. Aspreviously noted, the mandrel in this instance is stationaryand'nonrotating, while the developing tubing product is progressed alongthe mandrel by means such as described, the tube not being rotated onitsown axis but merely advanced lineally. Beyond the forward end of themandrel 5, at succeeding stages or stations of the process, theresinbonded cylindrical core or tube element itself is utilized as amandrel for the application of the intermediate and final layers ofveneer. In the illustrated example this bonded core or inner element ofthe tubing product comprises some ve 7 veneer layerslaidspirally andalternately of the opposite hand, the lparticular pluralityof suchlayersbeing selected as appropriate for the given tubing product.

The progressing ltubular core element on continuing its advance beyondstation -H comes next to a station I. Here a veneer strip G desirablyhaving Ythe grain disposed lengthwise the strip is superposed on thecore by laying it in the axial or longitudinal direction. Such veneerstrip S6 is ldrawn vfrom a prepared roll supply rotatably supported asupon a cross shaft 6I. The strip 'from such supply is led lengthwisebeneath the tubingcore and into and through a former or lfolding die S2.The latter serves to fold` the lengthwise-grained stripcircumferentially of the tubing core now serving as a mandrel, the strip'being of the appropriate'width such that its lo'ngitudinal side edgesare brought into close abutting but preferably non-overlapping relation,substantially as illustrated. The described laying and lateral wrappingof this longitudinal strip is accomplished by and in the course of thecontinuing forward progress of the tubing as a whole.

The veneer strip 6G carries or is supplied with a bonding agentsimilarly'as described in connection with the preceding stations and inthe course of the progress of the tube at station I it is subjected toheat andpressure desirably through the medium of pressure rolls 22, 22,as at the preceding stations. In this instance, and lthe same applies asto all following stations, diametrieally opposed pairs of the rolls 22are disposed in circuit to receive the heating current, as indicated` bythe plus and minus symbols on the drawing; that is, a pair of the rollsare utilized as the two electrodes of opposite polarity in lieu ofemployment of the interior mandrel as one electrode.

In some instances, but a single longitudinally applied strip such as 60may be employed, but generally a plurality of two or more are desirable,to provide a calculated axial strength and rigidity for the tubingproduct in combination with the underlying spirally laid and{predeterminedly radially rigid core layers. In the example of theaccompanying diagrammatic illustration, two such further applications oflengthwise stripping 'I and 80 are provided for, vat the stations J andK respectively. In all major respects the r procedure at thesestations'may be similar as at station I, the roll supplies rof preparedlengthwise-grained veneer stripping being rotatably 'supported on shafts1I, 8|, and the succeeding strips and 8U being conducted through foldingor forming dies l2 and 82 respectively. The progressing tube again issubjected to a heat and pressure treatment at each station, as by meansof thein'dic'ated electrode rolls 22, whereby each individuallongitudinal layer of the veneer is individually aswell as progressivelypolymerzed, set and dried.

At any convenient points with respect to the vseveral veneer layingstations, additional progressing stations are provided, one of which isindicatedat station L. The progressing or advancing means here may besimilar to that as described in connection with preceding stations D andH, including the progresser belt mechanism 25 and a speed control 2S.

Following application and setting of selected one or more lengthwiselaid veneer strips as at stations I, J and K, one or more outer or coverveneer layers are applied, these generally being laid spirally-similarly asat the core layer sta- 'these being laid of the oppositehand, indicated as l1-ight and left respectively at said stations M andN. At each of these latter stations or stages the tubing is subjected'to a heating and pressure treatment for the polymerizing of the bondingagentas previously described, pressure electrode rollers 22, 22being'indi'catedffor thepur- -pose on the drawing.

-A iinal progressing station is represented at O. This'may be understoodas similar to that as `re'itp'lained in connection with'precedingstations n. n and L,

V"ihe continuous forwardp'rogr'ess of the 'tubiii'g product beyondstation O brings it to lthe severing and delivery station such asdiagraminatically represented at P. -Automatic'o'rlother means is hereprovided for vcutting off the con'- tinuous tubing Api'oduct ofvindeterminate Alength into sections of Vany length, as may be vdesiredfor the given product and its use. -At the/station P a selected length-of the finished tubing product is indicated as a whole by the numeralT. It is adapted to be severedas by a swinging rotary cutter IGIoperated from the common 'drive shaft d through drive connectionsindicated as a whole at 52. For controlling the cutting time and pointan automatic and adjustable length Agauge |63 may be provided at theleading end of the vtubing T, the same being inovably supported andadapted to serve as a trip or stop, through connections as indicatedgenerally at 164.. Advancing engagement of the leading end of the tubingT against the trip or gauge l03 thus automatically brings the cutterVlill into operation, causing it to swing across the path of the tubingto sever the selected length thereof, the cutter mechanism being of thetimed progress type and synchronized with the progress of the tubingproduct so as to travel in synchronism with the latter during a cuttingoperation without interrupting or disturbing the continued forwardprogress of the following length of the tubing.

If preferred to rotate the mandreI andthe tubing formed upon it, thismay be-aec'omplished within the vscope oi the invention by revolvingthealternately'oppositely laid veneer roll supplies aboutthe tube andmandrel at twice the speed of rotation of the latter. The apparatus asdisclosedprovides for timing of the progress of the tubing and of thelaying of the Vvarious veneer layers to Y,conform them to the requiredtime interval for the polymerization of the bonding agent at eachstation, this in turn vbeing made possible by polymer-icing the tubeduring its processing at each station under a heat and pressuretreatment such as described. The invention includes the novel adaptationto this end of penetrative heating by electric energy whether or" theYhigh-frequency or radiofrequency character 4or of the transformer orresistance type -andwhereinat 'times aemandrel serves as an electrodeincooperation with outside pressure rollers or other members, or suchmembers in opposed pairs presenting both electrodes. Through theprogressive edge-turning or lateral wrapping, intirning or'foldingthrough folding dies as utilized for the length-grain veneer layers orplies or for the paper, veneer or other carrier strip 6, the rate ofapplication thereof may be coordinated with the other phases includingboth the Vinner or core stages and the exterior or cover stages, all inthe synchronized, automatic and continuous procedure afforded by theapparatus as herein illustrated and described by way of example. I

Our invention is not limited to the particular embodiment thereof asshown or described herein, its scope being pointed out in the followingclaims.

We claim:

1. Apparatus for the manufacture of Pluralply wood tubing comprising incombination, an elongated frame having initial, intermediate anddelivering sections defining a work path and presenting along it aplurality of stations in predetermined spaced relation, a formingmandrel extending longitudinally through and between an initialplurality of said stations, revoluble head means at the respectiveinitial Vstations for spirally wrapping individual supplies of veneerstripping in superposed tubular relation about the mandrel in diiferentwind directions at different stations, work-engaging means forcontinuously progressing the tubular work axially along the mandrel,veneer strip applying means at a succeeding station for supplying aveneer strip longitudinally to and laterally wrapping it about thespirally wrapped veneer layers, further spiral Wrapping means at astation subsequent to the longitudinal strip supplying station, anddrive mechanism for the wrapping and the progressing means coordinatedto present the resultant endless veneer tubing continuously at thedelivering section or" the frame.

2. Wood-Veneer tubing apparatus comprising, in combination, a stationaryforming mandrel, an initial plurality of oppositely rotating heads eachhaving means for rotatably supporting a roll supply of veneer strippingand wrapping the same spirally in closed tubular form about the mandrel,revoluble flat surfaced means for eX- ternally engaging and continuouslyadvancing the tubular Work, an intermediate plurality of longitudinalforming means disposed in immediate succession and positioned to delivera veneer strip longitudinally and to Wrap it laterally about theadvancing tubular work, a support for a veneer strip supply associatedwith each said means, a final plurality of revolving heads similar tothe initial heads for wrapping a corresponding number of spiral veneerstrips about the longitudinally laid and laterally Wrapped strips, andmeans for applying heat and pressure to each intermediate and i-lnalveneer strip immediately following the wrapping thereof thereby tointegrate it to that preceding by heat and pressure treatment of bondingmaterial between them, said heat and pressure applying means disposed inimmediately following succession to said intermediate forming and saidfinal Wrapping means.

PAUL R. GOLDMAN. RUDOLPH ALT.

REFERENCES CTED The following references are of record in the le of thispatent:

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